1. Field of the Invention
The present invention relates to an optical measuring device configured to illuminate a living tissue with measurement light, and based on a measurement value of the measurement light reflected and/or scattered from the living tissue, estimate characterization of the living tissue, and also relates to a fiber bundle association method.
2. Description of the Related Art
Conventionally, it is known that backscattering return light from a relatively weak scattering medium such as a living tissue is observed as interference enhanced light corresponding to the spatial coherence of the illumination light (see Young L. Kim, et. al, “Low-coherence enhanced backscattering; review of principles and applications for colon cancer screening”, Journal of Biomedical Optics, 11(4), 041125, 2006). A spectrum information measurement technology using this phenomenon is called low-coherence enhanced backscattering spectroscopy (LEBS), and characteristics of an interference pattern with respect to a scattering mean free path (reciprocal of a scattering coefficient) in a scattering medium are well studied (see V, Turzhitsky, et. al, “Characterization of Light transport in Scattering Media at Subdiffusion Length Scales with Low-Coherence Enhanced Backscattering”, IEEE journal of selected topics in quantum electronics, Vol. 16, No. 3, 619 (2010)). The scattering mean free path is correlated with the internal structural change of the scattering medium, which is used for detection of a minute tissue structural change which can be seen in early-stage cancer. For example, it is known that screening of colon cancer can be performed by using an interference pattern of scattering return light (see Hemant K. Roy, et. al, “Association between Rectal Optical Signatures and Colonic Neoplasia: Potential Applications for Screening”, Cancer Research, 69(10), 4476 (2009)).
Regarding the LEBS described above, a technique of applying the LEBS to non-invasive measurement in the body, through a measurement probe inserted in an endoscope, is known (see US 2009/0009759 A). In this technique, in order to obtain an interference pattern, a living tissue is illuminated with illumination light from the distal end of an illumination fiber of a measurement probe, and the intensity distribution of scattered light at a plurality of positions, which are correspond to scattering angles, are measured using a plurality of light-receiving fibers to thereby detect characterization of the living tissue.
Further, a technique of detecting characterization of a living tissue using a measurement probe, configured of a fiber bundle formed by bundling a plurality of optical fibers, is known (see U.S. Pat. No. 7,652,772 B). In this technique, characterization of a living tissue is detected by associating arrangements of the respective optical fibers on the end faces of the distal end portion and the proximal end portion of the fiber bundle.